The Cytopathology Section provides complete diagnostic service in exfoliative cytology and fine needle aspiration cytology. The section also routinely applies immunocytochemistry techniques to confirm and/or enhance cytological diagnostic accuracy. In addition, the section collaborates in various clinical research projects utilizing routine microscopy as well as special staining techniques, immunocytochemistry, and flow cytometry. The fine needle aspiration service is designed to afford maximal flexibility for clinicians and patients. Clinicians may request that: 1) a pathologist perform the aspiration; 2) a cytotechnologist assist the clinician in handling the specimen; 3) aspirations of deep lesions be performed by the radiologist with the assistance of a cytotechnologist to evaluate adequacy of the specimen. In conjunction with Dr. M.A. Stetler-Stevenson in the Hematopathology Section, we are initiating flow cytometry as an ancillary diagnostic technique in bladder washings. An example of one collaborative clinical research project involves clinical trials currently being conducted to study the use of the monoclonal antibody RFB4-RICIN A chain conjugate for refractory CD22 positive B-cell lymphoma. Our collaborative effort in this project involves the cytomorphologic evaluation of cytopathology specimens in order to: 1) document the presence of lymphoma and CD22 positivity prior to initiation of immunotoxin therapy and 2) monitor response by evaluating CD22 levels and presence of immunotoxin. Another collaborative project with the Whitman-Walker AIDS clinic is evaluating the prevalence of cervical premalignant lesions in HIV infected women. A few reports in the literature have cited a high rate of dysplasias in HIV infected women. These findings, if substantiated, have implications for cervical screening recommendations for this population.